classification of microorganism by Bilal Kakar University of Balochistan

2. MOHAMMAD BILAL KAKAR
DEPARTMENT OF MICROBIOLOGY
UNIVERSITY OF BALOCHISTAN

3.  Organizing, classifying
and naming living things
 Formal system originated
by Carl von Linné (1701-
1778)
 Identifying and classifying
organisms according to
specific criteria
 Each organism placed into
a classification system

4.  Domain
 Kingdom
 Phylum
 Class
 Order
 Family
 Genus
 species

5.  Eubacteria
 true bacteria, peptidoglycan
 Archaea
 odd bacteria that live in extreme environments,
high salt, heat, etc. (usually called extremophiles)
 Eukarya
 have a nucleus & organelles (humans, animals,
plants)

8.  4 main kingdoms:
 Protista
 Fungi
 Plantae
 Animalia
 Algae

9.  Binomial (scientific) nomenclature
 Gives each microbe 2 names:
 Genus - noun, always capitalized
 species - adjective, lowercase
 Both italicized or underlined
 Staphylococcus aureus (S. aureus)
 Bacillus subtilis (B. subtilis)
 Escherichia coli (E. coli)

10.  Changes favoring survival are retained and less
beneficial changes are lost
 All new species originate from preexisting
species
 Closely related organism have similar features
because they evolved from common ancestral
forms
 Evolution usually progresses toward greater
complexity

11. Insert figure 1.15
Woese-Fox System

13. 1. Microscopic morphology
2. Macroscopic morphology – colony
appearance
3. Physiological / biochemical characteristics
4. Chemical analysis
5. Serological analysis
6. Genetic and molecular analysis
• G + C base composition
• DNA analysis using genetic probes
• Nucleic acid sequencing and rRNA analysis

14.  Bergey’s Manual of Determinative Bacteriology –
five volume resource covering all known
procaryotes
 classification based on genetic information –
phylogenetic
 two domains: Archaea and Bacteria
 five major subgroups with 25 different phyla

15.  Vol 1A: Domain Archaea
 primitive, adapted to extreme habitats and modes of
nutrition
 Vol 1B: Domain Bacteria
 Vol 2-5:
 Phylum Proteobacteria – Gram-negative cell walls
 Phylum Firmicutes – mainly Gram-positive with low
G + C content
 Phylum Actinobacteria – Gram-positive with high G
+ C content

16.  Uses phenotypic qualities in identification
 restricted to bacterial disease agents
 divides based on cell wall structure, shape,
arrangement, and physiological traits

17.  Species
 collection of bacterial cells which share an overall similar
pattern of traits in contrast to other bacteria whose pattern
differs significantly
 Strain or variety
 culture derived from a single parent that differs in
structure or metabolism from other cultures of that species
(biovars, morphovars)
 Type
 subspecies that can show differences in antigenic makeup
(serotype or serovar), susceptibility to bacterial viruses
(phage type) and in pathogenicity (pathotype)

18.  Constitute third Domain Archaea
 Seem more closely related to Domain Eukarya than to
bacteria
 Contain unique genetic sequences in their rRNA
 Have unique membrane lipids and cell wall
construction
 Live in the most extreme habitats in nature,
extremophiles
 Adapted to heat, salt, acid pH, pressure and
atmosphere
 Includes: methane producers, hyperthermophiles,
extreme halophiles, and sulfur reducers

20.  Protista
 Fungi
 Plantae
 Animalia
 Algae

21.  Sexual reproduction
 Spores are formed following fusion of male and
female strains and formation of sexual structure
 Sexual spores and spore-forming structures
are one basis for classification
 Zygospores
 Ascospores
 Basidiospores

25.  Subkingdom Amastigomycota
 Terrestrial inhabitants including those of medical
importance:
1. Zygomycota – zygospores; sporangiospores and
some conidia
2. Ascomycota – ascospores; conidia
3. Basidiomycota – basidiospores; conidia
4. Deuteromycota – majority are yeasts and molds;
no sexual spores known; conidia

26.  Difficult because of diversity
 Simple grouping is based on method of
motility, reproduction, and life cycle
1. Mastigophora – primarily flagellar motility, some
flagellar and amoeboid; sexual reproduction; cyst
and trophozoite
2. Sarcodina – primarily ameba; asexual by fission;
most are free-living
3. Ciliophora – cilia; trophozoites and cysts; most are
free-living, harmless
4. Apicomplexa – motility is absent except male
gametes; sexual and asexual reproduction; complex
life cycle – all parasitic